Although the evidence for the Big Bang is overwhelming, what happened immediately after is a bit messy. But scientists think that "standard clock" signals in the early universe may provide an answer.

In a paper accepted for publication in the Journal of Cosmology and Astroparticle Physics, the international team describe how these standard clock signals generated massive particles whose signature might have left an impression on the cosmic microwave background (CMB), the afterglow of the Big Bang. These particles only existed for a fraction of a second in the early universe, and their formation depends strongly on what happened after the Big Bang.

Interestingly, fluctuations from the particles on the CMB may contain "time stamps" of the early universe, letting us pinpoint when certain events occurred.

"Ticks of these primordial standard clocks would create corresponding wiggles in measurements of the cosmic microwave background, whose pattern is unique for each scenario," said coauthor Yi Wang of The Hong Kong University of Science and Technology in a statement.

Detecting the particles would give us important information about cosmic inflation, the period of intense exponential expansion the universe underwent in its early instants. Although inflation is a single idea, there is an overwhelming number of models of cosmic inflation. Finding the correct one is a long and difficult process, but this new approach that could distinguish between the many inflationary scenarios.

The scientists want to use the variations in the CMB to understand what actually happened in the fraction of a second after the universe began. The previous studies focused on spatial variation, but the new method hopes to find temporal variations, time stamps of the different phenomena, now frozen together in the CMB.

"Imagine you took the frames of a movie and stacked them all randomly on top of each other. If those frames aren't labeled with a time, you can't put them in order," said coauthor Xingang Chen. "Did the primordial universe crunch or bang? If you don't know whether the movie is running forward or in reverse, you can't tell the difference."

^{The new theory could explain the early universe. pixelparticle/Shutterstock}

Inflation is generated by an energy field which permeates empty space. After the Big Bang, it was at a very high energy state. It then released the energy in a massive surge that created the sudden expansion of the universe. It didn’t last for more than 10^-32 seconds.

The Higgs’ field is an example of an energy field, and the Higgs’ boson is the particle that is created when the symmetry of the field is broken. Other energy fields had their symmetry broken during the inflationary period, so they generated massive particles at precise times.

Although current data is not accurate enough to spot these small variations, ongoing experiments such as BICEP3 and many others could soon reach the threshold for this signal to be detectable and hopefully allows scientists to refine the inflationary theory and solved the mystery of what happened after the Big Bang.